The present invention relates to a process camera for reproducing a plurality of originals on a single photosensitive member (hereinafter referred to as a "film").
Process cameras capable of reproducing multiple originals on a single film are already known from U.S. Pat. Nos. 3,998,546, 3,837,742, and 3,920,333, for example.
The conventional process cameras have a platen for holding a film, the platen being movable in X and Y directions in one plane normal to the optical axis of an object lens. Each time one page of an original has been reproduced on the film, the platen is moved in the X and Y directions and then a next page is reproduced on the film. Thereafter, necessary marks are printed on the film by contact printing on a printer. In this manner, a multiple pages of the original are successively reproduced on the film. Where the film is to be used as a direct printing plate, the plate can be completed by developing the images on the film.
The known process cameras, however, only reproduce originals on films. After the original has been reproduced on the film, a signature and other register marks are reproduced on the film by contact printing on a printer, and then the images are developed by an image developing machine. These processing steps must be carried out by manually processing the film in a dark room.
Generally, the images of an original are reproduced as full size images without magnification in a process camera. However, there are instances where the images of an original should be enlarged or reduced in size. For enlarging or reducing an image and also obtaining a full size image, it is necessary to set the optical system to suitable magnifications. The magnification m of an optical system is expressed by: EQU m=f/(u-f)=(v-f)/f
where f is the focal length of the object lens, u is the distance from the principal point of the lens to the object to be photographed, and v is the distance from the principal point of the lens to the image formed by the optical system. For varying the magnification, therefore, the parameter u or v should be varied. If the parameter u or v is varied with the same lens employed, the total optical path length from the object to the image is varied.
In order to reproduce an image of an original properly in a desired position on a film in a process camera, the original should properly be positioned with respect to the subject holder. One conventional practice to meet this requirement has been to provide one side edge of the original table with a plurality of register pins, define a plurality of holes or recesses in one side edge of the original or a support base to which the original is attached, and fitting or holding the holes or recesses in or against the register pins for the positioning of the original. This procedure however requires a preparatory process for defining the positioning holes or recesses in the original, and is hence complex.
Some printing plates are produced by the diffusion transfer process which utilizes a positive-positive film, e.g., a support coated with a silver halide emulsion layer and a physical development nuclei layer. In such a printing plate, the other area than an original reproduced on the printing plate is not exposed to light, and the silver halide in the unexposed area is diffused into the physical developing speck layer by the diffusion transfer developing process. As a result, metal silver is deposited, and ink would be received by the metal silver deposit, so that a non-image area outside of the printed page would be printed in black. Therefore, the non-image area outside of the printed page should be exposed to light so as to eliminate any black non-image area. The conventional process cameras, however, cannot eliminate such black non-image areas. It has been customary to remove the film from the camera after an original has been reproduced, cover the reproduced original area on the film with a mask plate, set the film in a printer, and expose the film to light for thereby eliminating any black non-image area. Since these steps have to be effected in a dark room, the entire process is tedious and time-consuming.
If a plurality of images or originals are to be reproduced on one film in a certain format, the originals have to be set in a certain orientation. Inasmuch as each original may not be directed in the same orientation, the originals may often be directed in error.
A film is in the form of a roll stored in a cartridge, and the cartridge is located in a cartridge loading unit in a process camera. The roll film is however considerably heavy, and it has been difficult for one operator to load the cartridge with the roll film stored therein into the cartridge loading unit.
In conventional process cameras, an unexposed film is manually set on the platen, or an exposed film is manually removed from the platen. Consequently, this process is poor in efficiency, and requires a lot of manual labor.
Moreover, conventional process cameras employ films with predefined pinholes or recesses. The film can be set on the platen by fitting guide pins on the platen into the pinholes or recesses. The film has to be manually set on the platen in a dark room, a procedure which is time-consuming and tedious, and is of low efficiency.